The zoom tool magnifies or shrinks the map view. There are three separate functions bundled into the zoom tool:
Ø Zoom In
Click with your mouse to zoom in one level closer. The new view is centered over the cursor position.
Ø Zoom Out
Right-click to zoom out one level further away.
Ø Zoom Box
Click and drag a region with the cursor. After you release, the view will be changed to contain the selected area.